Chevrolet and GMC on Thursday unveiled their long-awaited 2014 pickups, which feature strong, familiar styling, a new class of engines and nicer interiors.

The engines — a 4.3-liter V-6, 5.3-liter V-8 and 6.2-liter V-8 — and the trucks’ dated interiors got most of the major upgrades in the trucks, which should be available next summer.

For example, the high-compression engines in the full-size Chevy Silverado and GMC Sierra will be equipped with direct fuel injection, variable cam timing and cylinder deactivation for better economy.

But both trucks’ chassis, cabs, suspensions, brakes and steering also received numerous refinements.

“The new trucks are better in every way and dramatically better in some ways,” said Jeff Luke, executive chief engineer of full- and midsize trucks at General Motors.

The trucks are critical to GM, which is still recovering from its bankruptcy and restructuring in 2009.

Though the current Silverado is six model years old, it remains GM’s best-selling vehicle in the U.S. — 415,130 pickups last year, second only to the Ford F-series trucks.

“I think GM did a nice job with them,” said Jesse Toprak, vice president of industry trends and insights for TrueCar.com. “But the true test is to hit the market and see what happens.”

At one time, full-size pickups probably generated profits of $10,000 each for automakers, Toprak noted. As the content and complexity of the trucks have increased, that has likely dropped to $5,000 or so per truck.

“The point is it is still a highly profitable segment,” he said.

GM declined to release horsepower, torque and fuel economy numbers for the new engines and may be saving them for the upcoming Detroit auto show.

But Luke expects the engines to be best in class in most measurements.

All trucks will come standard with six-speed automatics.

The new all-aluminum engines, called EcoTec3, will shift from six or eight cylinders to four to save fuel when power demands are low.

Pricing on the trucks will be announced closer to their launch in the second quarter.

“Historically, the recipe was simple for updating a pickup,” said Mike Jackson, director of North American production forecasting at IHS Automotive. “You made it bigger and more powerful. It’s a whole lot more complicated now.”

The overall dimensions of the trucks and their weight — typically 5,000 pounds or more — remain mostly unchanged from current pickups.

But engineers reconfigured the trucks’ cabs, adding 2 inches of leg space in the back seats of crew-cab pickups by shortening the length of the front doors.

Both trucks get dramatically improved interiors with big instrument panels and center stacks and more refined plastics, leather and cloth.

While substantially better, the new trucks still face enormous competition in the full-size pickup segment — the fourth-largest segment in the industry with 1.6 million buyers last year.

Ford and Ram also have new trucks, and both are more economical and sophisticated than GM’s current pickups.

“The big day will be when we get them,” said Tom Durant, owner of Classic Chevrolet in Grapevine, which for several years has been the largest Chevy retailer in the U.S. and a major seller of trucks.

“I think we will do well with it,” Durant said. “But it will just take awhile before we get a full inventory and can really take advantage of it.”